In clinical laboratory tests, blood collection containers are widely used to accommodate blood samples. When a blood collection container that contains a serum- or plasma-separating composition therein is used for blood collection, appropriate adjustment of the specific gravity of the serum- or plasma-separating composition enables centrifugation of a serum component or plasma component from whole blood using of a difference in specific gravities.
The interior of blood collection containers is required to be in a sterilized state by ISO and JIS standards, from the viewpoint of preventing bacterial infection of patients. Thus, sterilization with electron beams, γ rays or the like carried out in the production step, during which changes in the physical properties of the separating composition may be caused. Containers for blood collection are often stored for a prolonged period until use in hospitals. Also in such cases, changes in the physical properties of the separating composition may be caused due to prolonged storage.
When the above changes in the physical properties are caused, there is a known trouble in which a serum component or plasma component cannot be separated from whole blood using a difference in specific gravities even if predetermined centrifugation is conducted. When the centrifuge is small one or old one, which fails to impart desired centrifugal force, this phenomenon would be a more significant problem.
There is a need for a serum- or plasma-separating composition for blood collection containers capable of reducing decrease in the blood separation performance due to changes in the physical properties, even under conditions of storage for a prolonged period as described above.
The following Patent Literature 1 discloses a serum- or plasma-separating composition comprising an acryl-based resin as base material.
The following Patent Literature 2 discloses a serum- or plasma-separating composition comprising polyalkylene glycol added, in response to the above-described problem.